简介:Withtherapiddevelopmentofglobalinformationhighway,multimediacommunicationtechnologyplaysamoreandmoreimportantroleinnationaleconomicandsocialdevelopment.However,themultimediacommunicationsystemisacomplicatedrealtimedistributedsystemanditssoftwareisdifficulttodevelop.Inordertoimprovetherapiddevelopmentandapplicationofthemultimediacommunicationtechnology,thereisanurgentneedtocarryoutthebasicresearchworkofsoftwaredevelopmentplatforminthisfield.
简介:Title:DiscontinuousDeformationAnalysisandRecentCrustalMovementAuthor:WANGZeminSupervisor:LIUJingnanThestudyfocusesonthewait_to_be_resolvedimportantdifficultproblem—howtoanalyzeandprocessthenumerousdataofcrustalmovementgainedbyrecentmeasuringmethodsoastodiscovertheinnermechanisms,thispaper,adopt
简介:Airborne3DimagewhichintegratesGPS,attitudemeasurementunit(AMU),scanninglaserrangefinder(SLR)andspectralscannerhasbeendevelopedsuccessfully.ThespectralscannerandSLRusethesameopticalsystemwhichensureslaserpointtomatchpixelseamlessly.Thedistinctiveadvantageof3Dimageisthatitcanproducegeo_referencedimagesandDSM(digitalsurfacemodels)imageswithoutanygroundcontrolpoints(GCPs).ItisnolongernecessarytosurveyGCPsandwithsomesoftwaresthedatacanbeprocessedandproducedigitalsurfacemodels(DSM)andgeo_referencedimagesinquasi_real_time,therefore,theefficiencyof3Dimageis10~100timeshigherthanthatoftraditionalapproaches.Theprocessingprocedureinvolvesdecomposingandcheckingtherawdata,processingGPSdata,calculatingthepositionsoflasersamplepoints,producinggeo_referencedimage,producingDSMandmosaicingstrips. Theprincipleof3Dimageisfirstintroducedinthispaper,andthenwefocusonthefastprocessingtechniqueandalgorithm.Theflighttestsandprocessedresultsshowthattheprocessingtechniqueisfeasibleandcanmeettherequirementofquasi_real_timeapplications.
简介:Severaldifferentstrategiesof3Dmodelingareadoptedfordifferentkindsofmanmadeobjects.Firstly,forthosemanmadeobjectswithregularstructure,if2Dinformationisavailableandelevationinformationcanbeobtainedconveniently,then3Dmodelingofthemcanbeexecuteddirectly.Secondly,forthosemanmadeobjectswithcomplicatedstructurecomparativelyandrelatedstereoimagespaircanbeacquired,inthelightoftopology-based3Dmodelwefinish3Dmodelingofthembyintegratingautomaticandsemi-automaticobjectextraction.Thirdly,forthemostcomplicatedobjectswhosegeometricalinformationcannotbegotfromstereoimagespaircompletely,weturntotopological3DmodelbasedonCAD.
简介:SegmentationandedgeregulationarestudieddeeplytoextractbuildingsfromDSMdataproducedinthispaper.Buildingsegmentationisthefirststeptoextractbuildings,andanewsegmentationmethod-adaptiveiterativesegmentationconsideringratiomeansquare-isproposedtoextractthecontourofbuildingseffectively.Asub-image(suchas50×50pixels)oftheimageisprocessedinsequence,theaveragegraylevelanditsratiomeansquarearecalculatedfirst,thenthresholdofthesub-imageisselectedbyusingiterativethresholdsegmentation.Thecurrentpixelissegmentedaccordingtothethreshold,theaver-agegraylevelandtheratiomeansquareofthesub-image.Theedgepointsofthebuildingaregroupedaccordingtotheazimuthofneighborpoints,andthentheoptimalazimuthofthepointsthatbelongtothesamegroupcanbecalculatedbyusinglineinterpolation.
简介:Thispaperdemonstratesanexperimentonthegenerationof3Dvirtualgeographicenvironmentonthebasisofexperimentalflightlaserscanningdatabyasetofalgorithmsandmethodsthatweredevelopedtoautomaticallyinterpretrangeimagesforextractinggeo-spatialfeaturesandthentoreconstructgeo-objects.Thealgorithmsandmethodsfortheinterpretationandmodelingoflaserscannerdataincludetriangulated-irregular-network(TIN)-basedrangeimageinterpolation;mathematical-morphology(MM)-basedrangeimagefiltering,featureextractionandrangeimagesegmentation,featuregeneralizationandoptimization,3Dobjectsreconstructionandmodeling;computergraphics(CG)-basedvisualizationandanimationofgeographicvirtualrealityenvironment.
简介:Dataacquisitionandmodelingarethetwoimportant,difficultandcostfulaspectsinaCybercityproject.2D-GISismatureandcanmanagealotofspatialdata.Thus3D-GISshouldmakethebestofdataandtechnologyof2D-GIS.ConstructionofausefulsyntheticenvironmentrequiresintegrationofmultipletypesofinformationlikeDEM,textureimagesand3Drepresentationofobjectssuchasbuildings.Inthispaper,themethodfor3Dcitylandscapedatamodelandvisualizationbasedonintegrateddatabasesispresented.Sincethedatavolumeofrasterareveryhuge,specialstrategies(forexample,pyramidgriddedmethod)mustbeadoptedinordertomanagerasterdataefficiently.Threedifferentmethodsofdataacquisition,theproperdatastructureandasimplemodelingmethodarepresentedaswell.Atlast,apilotprojectofShanghaiCybercityisillustrated.
简介:Basedonthearchitecturalsurveyprojectof“theChiLinNunneryRedevelopment'inHongKong,thispaperattemptstoinvestigatethetechniquesofbuilding3Ddigitaldocumentoflarge_scaletimberstructureandqualitycontrolduringconstructionbycomputer_based3Dsimulationforthewholeproject.Therewereseveralkeyissuesincludingprimarydataacquisition,3Dmodelinganddisplay,pre_assemblingthetotalbuildingandqualityexamination,etc.Inthispaper,someusefulexperiments,suchasthenewapplicationsofCCDdigitalcameras,imageandgraphprocessingsoftwarepackages(CAD,Photoshop,Photomodeler,Vexcel,etc.)tothearchitecturesarealsopresented.Thesemethodsintroducedinthispaperaresuitableforimageandgraphintegrateddatabasebuildingofcomplicatedarchitectures,andusefulforconvenientlymaintainingandreconstructingtheancientarchitectures.
简介:构造一个煤矿的虚拟景色是的3D为在煤采矿上现代化并且处理信息的客观要求生产。建立“一个数字矿”也是关键技术。由探索当前的世界范围的研究,软件和硬件工具和应用程序要求,与案例研究地点(Pingdingshan煤组的Daz-huang矿)结合了,为一个矿的3Dgeo可视化的一条途径出现工厂和矿车道深深地被讨论。在这研究,虚拟景色基于弧/信息和Site-Builder3D被学习的为一个大范围的快速的建模方法,和从2D景色的3D景色的自动产生被认识到。能从2D把矿车道系统变换成3D的如此的一个自动方法为Dazhuang矿被认识到。一些相关应用程序问题被学习,包括在在矿表面的虚拟景色的虚拟场面种的2D和3D和矿车道之间的属性质问,并列质问,距离措施,碰撞察觉和动态相互作用。一个原型系统被设计并且发展。
简介:Thispaperintroducestheprocessofmaking3DvectorscenographofanancientbuildingwithlargequantitiesofdatawiththeaidofAutoCAD,whichdisplaystheeffectofscenerydrawings.ThevitalskillsandtechniqueinvolvedareillustratedthroughtheexampleofPagodaofThousandsofBuddhainChiLinNunneryinHongKong.Thisconstructionwasstartedin1996andfinishedin1999withtheconcretestructureinternalandwoodexternal,imitatingthestyleofbuildingsinTangDynasty.Thus,3Dvectorscenographbecomeavailabletousers.
简介:为3D城市建模的OGC标准广泛地在越来越多的应用被使用。它定义详细(到有增加精确性和结构的复杂性的LoD4的LoD0)的五个连续层次,在哪个LoD3包括所有外面的外观和几何细节并且随后要求许多存储空间。新LoD与象窗户,门以及更小的fa一样的LoD3模型和开的目标的外面的壳作为壳模型被介绍?果汁饮料目标被投射到墙上。在这份报纸,用户调查被介绍。这的结果调查壳模型能几乎给用户的表演象LoD3模型的一样的视觉印象。Furthermroe,算法被开发从LoD3提取壳模型模型。实验证明这个壳模型能减少原来的LoD3模型的多达90%存储。因此,一方面,它能为一个LoD3模型被用作一个代用品为小显示上的可视化。在另一方面,它能在CityGML被当作详细(SLoD3)的分段,自从它几乎保留信息的一样的数量,但是要求少得多存储空间。